System1 Designs's line of silicone couplers feature 3 layers of polyester reinforcement and are suitable for applications with boost pressures up to 45psi. They also feature a temperature rating of 428°F for direct to turbocharger installations. Leg Length: 3.5" Size: 3.5" Material: 3-ply Polyester Reinforced Temp: 428 Degrees F (220 C).